======================================
| [   13.825269][    C3] 1 lock held by ksoftirqd/3/32:
| [ 13.825462][ C3] #0: ffffffffb15774c0 (rcu_callback){....}-{0:0}, at: rcu_do_batch (./include/linux/rcupdate.h:331 kernel/rcu/tree.c:2570) 
| [   13.825798][    C3]
| [   13.825798][    C3] stack backtrace:
[   13.826036][    C3] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   13.826038][    C3] Call Trace:
[   13.826040][    C3]  <TASK>
[ 13.826043][ C3] dump_stack_lvl (lib/dump_stack.c:123) 
[ 13.826050][ C3] print_usage_bug.part.0 (kernel/locking/lockdep.c:4048) 
[ 13.826055][ C3] mark_lock_irq (kernel/locking/lockdep.c:4013 kernel/locking/lockdep.c:4059 kernel/locking/lockdep.c:4270) 
[ 13.826060][ C3] ? __pfx_unwind_next_frame (arch/x86/kernel/unwind_orc.c:469) 
[ 13.826067][ C3] ? save_trace (kernel/locking/lockdep.c:595) 
[ 13.826071][ C3] mark_lock (kernel/locking/lockdep.c:4756) 
[ 13.826075][ C3] mark_usage (kernel/locking/lockdep.c:4645) 
[ 13.826078][ C3] __lock_acquire (kernel/locking/lockdep.c:5194) 
[ 13.826082][ C3] ? __lock_acquire (kernel/locking/lockdep.c:5240) 
[ 13.826086][ C3] lock_acquire.part.0 (kernel/locking/lockdep.c:473 kernel/locking/lockdep.c:5873) 
[ 13.826090][ C3] ? simple_pin_fs (fs/libfs.c:1067) 
[ 13.826093][ C3] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:745) 
[ 13.826100][ C3] ? lock_acquire (./include/trace/events/lock.h:24 kernel/locking/lockdep.c:5834) 
[ 13.826103][ C3] ? simple_pin_fs (fs/libfs.c:1067) 
[ 13.826107][ C3] _raw_spin_lock (./include/linux/spinlock_api_smp.h:134 kernel/locking/spinlock.c:154) 
[ 13.826110][ C3] ? simple_pin_fs (fs/libfs.c:1067) 
[ 13.826113][ C3] simple_pin_fs (fs/libfs.c:1067) 
[ 13.826116][ C3] debugfs_remove (fs/debugfs/inode.c:805 fs/debugfs/inode.c:799) 
[ 13.826119][ C3] ref_tracker_dir_exit (lib/ref_tracker.c:412 lib/ref_tracker.c:196) 
[ 13.826126][ C3] ? __pfx_ref_tracker_free (lib/ref_tracker.c:254) 
[ 13.826128][ C3] ? __sk_destruct (./include/linux/instrumented.h:96 ./include/linux/atomic/atomic-instrumented.h:400 ./include/linux/refcount.h:389 ./include/linux/refcount.h:432 ./include/linux/refcount.h:450 ./include/net/net_namespace.h:287 ./include/net/net_namespace.h:390 net/core/sock.c:2376) 
[ 13.826135][ C3] ? rcu_do_batch (kernel/rcu/tree.c:2576) 
[ 13.826138][ C3] ? __pfx_ref_tracker_dir_exit (lib/ref_tracker.c:190) 
[ 13.826141][ C3] ? smpboot_thread_fn (kernel/smpboot.c:164 (discriminator 3)) 
[ 13.826146][ C3] ? kthread (kernel/kthread.c:464) 
[ 13.826152][ C3] ? ret_from_fork (arch/x86/kernel/process.c:148) 
[ 13.826156][ C3] ? ret_from_fork_asm (arch/x86/entry/entry_64.S:258) 
[ 13.826159][ C3] ? migrate_enable (./arch/x86/include/asm/preempt.h:104 ./include/linux/preempt.h:481 ./include/linux/preempt.h:481 kernel/sched/core.c:2427) 
[ 13.826165][ C3] ? __pfx_migrate_enable (kernel/sched/core.c:2402) 
[ 13.826171][ C3] __put_net (net/core/net_namespace.c:732) 
[ 13.826176][ C3] __sk_destruct (./include/net/net_namespace.h:288 ./include/net/net_namespace.h:390 net/core/sock.c:2376) 
[ 13.826180][ C3] ? rcu_do_batch (kernel/rcu/tree.c:2576) 
[ 13.826183][ C3] rcu_do_batch (kernel/rcu/tree.c:2576) 
[ 13.826188][ C3] ? __pfx_rcu_do_batch (kernel/rcu/tree.c:2500) 
[ 13.826192][ C3] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:745) 
[ 13.826195][ C3] ? note_gp_changes (kernel/rcu/tree.c:1326 (discriminator 1)) 
[ 13.826198][ C3] ? lockdep_hardirqs_on (kernel/locking/lockdep.c:4475) 
[ 13.826205][ C3] rcu_core (kernel/rcu/tree.c:2834) 
[ 13.826211][ C3] handle_softirqs (kernel/softirq.c:579) 
[ 13.826215][ C3] ? __pfx_run_ksoftirqd (kernel/softirq.c:961) 
[ 13.826219][ C3] run_ksoftirqd (kernel/softirq.c:436 kernel/softirq.c:969 kernel/softirq.c:960) 
[ 13.826222][ C3] smpboot_thread_fn (kernel/smpboot.c:164 (discriminator 3)) 
[ 13.826225][ C3] ? __pfx_smpboot_thread_fn (kernel/smpboot.c:107) 
[ 13.826229][ C3] kthread (kernel/kthread.c:464) 
[ 13.826232][ C3] ? __pfx_kthread (kernel/kthread.c:413) 
[ 13.826234][ C3] ? ret_from_fork (arch/x86/kernel/process.c:147) 
[ 13.826237][ C3] ? __lock_release (kernel/locking/lockdep.c:5539) 
[ 13.826241][ C3] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:745) 
[ 13.826244][ C3] ? __pfx_kthread (kernel/kthread.c:413) 
[ 13.826247][ C3] ret_from_fork (arch/x86/kernel/process.c:148) 
[ 13.826250][ C3] ? __pfx_kthread (kernel/kthread.c:413) 
[ 13.826253][ C3] ret_from_fork_asm (arch/x86/entry/entry_64.S:258) 
| [   13.837367][    C3] RCU nest depth: 0, expected: 0
| [   13.837544][    C3] INFO: lockdep is turned off.
| [   13.837719][    C3] Preemption disabled at:
| [ 13.837721][ C3] handle_softirqs (kernel/softirq.c:553) 
[   13.838062][    C3] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   13.838064][    C3] Call Trace:
[   13.838066][    C3]  <TASK>
[ 13.838068][ C3] dump_stack_lvl (lib/dump_stack.c:123) 
[ 13.838075][ C3] __might_resched (kernel/sched/core.c:8796) 
[ 13.838084][ C3] down_write (./include/linux/kernel.h:73 kernel/locking/rwsem.c:1576) 
[ 13.838088][ C3] ? __pfx_down_write (kernel/locking/rwsem.c:1575) 
[ 13.838091][ C3] ? simple_recursive_removal (fs/libfs.c:614) 
[ 13.838096][ C3] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:745) 
[ 13.838102][ C3] ? do_raw_spin_unlock (./arch/x86/include/asm/atomic.h:23 ./include/linux/atomic/atomic-arch-fallback.h:457 ./include/linux/atomic/atomic-instrumented.h:33 ./include/asm-generic/qspinlock.h:57 kernel/locking/spinlock_debug.c:101 kernel/locking/spinlock_debug.c:141) 
[ 13.838106][ C3] simple_recursive_removal (./include/linux/dcache.h:409 ./include/linux/dcache.h:424 ./include/linux/dcache.h:434 fs/libfs.c:617) 
[ 13.838109][ C3] ? do_raw_spin_unlock (./arch/x86/include/asm/atomic.h:23 ./include/linux/atomic/atomic-arch-fallback.h:457 ./include/linux/atomic/atomic-instrumented.h:33 ./include/asm-generic/qspinlock.h:57 kernel/locking/spinlock_debug.c:101 kernel/locking/spinlock_debug.c:141) 
[ 13.838111][ C3] ? __pfx_remove_one (fs/debugfs/inode.c:780) 
[ 13.838117][ C3] debugfs_remove (fs/debugfs/inode.c:806 fs/debugfs/inode.c:799) 
[ 13.838120][ C3] ref_tracker_dir_exit (lib/ref_tracker.c:412 lib/ref_tracker.c:196) 
[ 13.838125][ C3] ? __pfx_ref_tracker_free (lib/ref_tracker.c:254) 
[ 13.838127][ C3] ? __sk_destruct (./include/linux/instrumented.h:96 ./include/linux/atomic/atomic-instrumented.h:400 ./include/linux/refcount.h:389 ./include/linux/refcount.h:432 ./include/linux/refcount.h:450 ./include/net/net_namespace.h:287 ./include/net/net_namespace.h:390 net/core/sock.c:2376) 
[ 13.838132][ C3] ? rcu_do_batch (kernel/rcu/tree.c:2576) 
[ 13.838136][ C3] ? __pfx_ref_tracker_dir_exit (lib/ref_tracker.c:190) 
[ 13.838139][ C3] ? smpboot_thread_fn (kernel/smpboot.c:164 (discriminator 3)) 
[ 13.838141][ C3] ? kthread (kernel/kthread.c:464) 
[ 13.838145][ C3] ? ret_from_fork (arch/x86/kernel/process.c:148) 
[ 13.838149][ C3] ? ret_from_fork_asm (arch/x86/entry/entry_64.S:258) 
[ 13.838153][ C3] ? migrate_enable (./arch/x86/include/asm/preempt.h:104 ./include/linux/preempt.h:481 ./include/linux/preempt.h:481 kernel/sched/core.c:2427) 
[ 13.838157][ C3] ? __pfx_migrate_enable (kernel/sched/core.c:2402) 
[ 13.838163][ C3] __put_net (net/core/net_namespace.c:732) 
[ 13.838167][ C3] __sk_destruct (./include/net/net_namespace.h:288 ./include/net/net_namespace.h:390 net/core/sock.c:2376) 
[ 13.838171][ C3] ? rcu_do_batch (kernel/rcu/tree.c:2576) 
[ 13.838174][ C3] rcu_do_batch (kernel/rcu/tree.c:2576) 
[ 13.838179][ C3] ? __pfx_rcu_do_batch (kernel/rcu/tree.c:2500) 
[ 13.838183][ C3] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:745) 
[ 13.838186][ C3] ? note_gp_changes (kernel/rcu/tree.c:1326 (discriminator 1)) 
[ 13.838189][ C3] ? lockdep_hardirqs_on (kernel/locking/lockdep.c:4475) 
[ 13.838195][ C3] rcu_core (kernel/rcu/tree.c:2834) 
[ 13.838199][ C3] handle_softirqs (kernel/softirq.c:579) 
[ 13.838204][ C3] ? __pfx_run_ksoftirqd (kernel/softirq.c:961) 
[ 13.838208][ C3] run_ksoftirqd (kernel/softirq.c:436 kernel/softirq.c:969 kernel/softirq.c:960) 
[ 13.838211][ C3] smpboot_thread_fn (kernel/smpboot.c:164 (discriminator 3)) 
[ 13.838213][ C3] ? __pfx_smpboot_thread_fn (kernel/smpboot.c:107) 
[ 13.838217][ C3] kthread (kernel/kthread.c:464) 
[ 13.838220][ C3] ? __pfx_kthread (kernel/kthread.c:413) 
[ 13.838222][ C3] ? ret_from_fork (arch/x86/kernel/process.c:147) 
[ 13.838225][ C3] ? __lock_release (kernel/locking/lockdep.c:5539) 
[ 13.838230][ C3] ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:745) 
[ 13.838234][ C3] ? __pfx_kthread (kernel/kthread.c:413) 
[ 13.838237][ C3] ret_from_fork (arch/x86/kernel/process.c:148) 
[ 13.838240][ C3] ? __pfx_kthread (kernel/kthread.c:413) 


Finger prints:
handle_softirqs:dump_stack_lvl:__might_resched:down_write:simple_recursive_removal
mark_lock_irq:mark_lock:mark_usage:__lock_acquire:_raw_spin_lock